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ePaper created 2016-04-05, 09:23:03 | version 1.38.0
211_2016 case report _ implant restorations Generally, overdentures offer several advantages over conventional removable prostheses, including improved stability, functionality, comfort, confidence in the ability to interact socially, straight forward rehabilitation and easy maintenance for the patient. Quite simply, overdentures result in a significant improvement in the quality of life of the patient. In our case, a 58-year-old patient pre- sented at the practice with discomfort caused by her complete maxillary denture. When looking at her history, we found a prosthetic restoration retained on six im- plants in the lower jaw and a complete max- illary denture that was aesthetically and functionally inadequate (Fig. 1). An initial aesthetic evaluation established that the shape and shade of the teeth were inap- propriate. In addition, the midline was mis- aligned and the curvature of the maxillary anterior teeth was shaped incorrectly. The poor stability of the denture was caused by insufficient prosthetic support and by the method with which it had been produced. Taking the patient’s requirements and financial constraints, as well as the clinical condition of the maxillary prosthetic field, into account, we decided in favour of an implant-supported prosthetic treatment modality. The plan was to insert four maxil- lary implants to retain an overdenture pros- thesis using the double-crown method. This procedure is frequently followed in such cases and has seen constant improvement with the emergence of new technologies and materials. Our protocol required primary telescope crowns milled from zirconia at an incline of 2 degrees and secondary copings obtained by electroforming. This approach combines the advantages of zirconia (primary telescopes) with those of hydraulic retention (galvanic copings). After a complication-free period of healing and osseointegration, the four im- plants were uncovered and a preliminary im- pression was taken. Also, a customised tray was created from the resulting model. In order to proceed to the next stage of the treatment, we required a functional im- pression that would transfer the exact po- sition of the implants. For this purpose, the four impression posts were splinted togeth- er on a custom tray with composite material (Figs. 2 & 3). After creating the working models (Fig. 4), we determined the patient’s vertical di- mension of occlusion, the length of the fu- ture teeth, as well as the gingival smile line, by means of an occlusal plate (bite rim). In Fig. 5_The models mounted on the articulator clearly demonstrate the challenges involved in this clinical case. Fig. 6_Try-in of the wax set-up and evaluation of the aesthetic parameters. Fig. 7_Customised titanium abutments. Fig. 8_Reconstruction of the primary structure after scanning the model, abutments and set-up. Fig. 5 Fig. 7 Fig. 6 Fig. 8